Automobile vehicles HVAC systems for treating and conditioning the ambient air inside the vehicle. These systems comprise a heater and an air conditioner. The heater warms the air that is recirculated in the vehicle and the air that is brought into the vehicle from the atmosphere surrounding the vehicle. The air conditioner dries the air that is both in recirculated in the vehicle and introduced from the atmosphere. Most of the currently available passenger vehicles have a continuous ventilation system. That is a portion of the air in the vehicle is discharged or vented from the vehicle and replacement air is introduced into the vehicle.
The vented air is generally expelled through the rear of the vehicle and the replacement air is brought in through the front of the vehicle. The air entering the vehicle passes through a cowl panel and plenum adjacent the outer edge of the front windshield. The cowl panel has a screen that prevent debris from entering the plenum. The plenum has drain passages that collect the liquid, such as rain water, and prevent it from continuing with the incoming air that enters the interior of the vehicle.